Barrie Manikel, Director

Focus On Imputs

Morris, Manitoba

Glyphosate appears to have potential as a desiccant in cereal and oilseed production. The "fit" it takes in a zero tillage program depends on the crop, the weed spectrum in that crop, and to a certain extent, what it is that you want to accomplish. I believe that this herbicide will have a good fit to zero tillage for a number of reasons:

1. It can be applied to uneven stands with good results

2. Desiccation is complete, down to the ground

3. Perennial weed control appears to be very good

4. Crop yields and quality are not affected

5. Chemical residues have not been found in the crop

6. It will advance harvest in many situations

7. It can make harvesting easier & faster

8. It may reduce annual weed seed viability

On the other side of the coin, we have found some negative effects:

1. Germination of the seed can be severely affected

2. Some crops do not have the straw strength needed.

Focus On Inputs Association has been testing glyphosate for the past two years on the Prairies, but I will concentrate on this year's results in Manitoba. The trials were all applied using a 256 Versatile Bi Directional tractor, which was supplied courtesy of Versatile-Ford-New Holland, Winnipeg. We mounted a 43 foot (13.l m) boom on the rear 3 point hitch. This provided clearance in all crops. The tractor was equipped with 10.4 x 38 tires, which aided the under the tractor clearance and reduced the tractor tracking. Three stainless steel tanks held the three rates of glyphosate used in all trials (1/2, 1 and 2 litre per acre rate of glyphosate. Agrol 90 was added to the 1/2 1/ac. rate. All applications were made using 40 psi(275 kpa) and 7.5 gal/acre (34 1/ac) water rates. Tractor speed was 6 mph (9.65 km/h) in all but the roughest fields. The 256 Versatile had the power and maneuverability to do the job well.

Note: The use of glyphosate as a desiccant has been researched by Focus On Inputs, a farm organization, and all funding for the research outlined in this paper has been provided by the membership. This research has been conducted with a research permit. The use of glyphosate as a desiccant is not yet registered and until this application is registered no one should consider applying glyphosate as a desiccant.

FIELD RESEARCH TRIALS

The trials Focus On Inputs conducted in Manitoba were centered in the Red River Valley, near Brandon and near Minnedosa The use of field size equipment placed a restriction on mobility. Each rate of chemical was sprayed with a 43 foot boom mounted on the 256 Versatile. Generally the trials ran 1/3 to 1/2 mile in length, were harvested with a regular combine using a straight cut header. Yields were measured with an electronic weigh wagon.

The research sites were chosen to allow us to evaluate how well glyphosate would desiccate the crop, and its effects on annual and perennial weeds. Yield comparisons reflect differences in weed populations between plots as well as differences due to the desiccant.

TIME OF APPLICATION

To be used successfully glyphosate must be applied while the crop is still green, and about 10 to 15 days prior to normal swathing. It has been our experience that wheat can be sprayed when the seed is in the dough stage. Unevenness in the field usually results in some seed being in the soft dough, the majority fairly firm, and the balance is mature seed. As you can see from the slides, the crop at time of spraying is still quite green, with just the initial goldness of turning evident. The greener the seed, the greater the reduction in germination. This year it was an exceptionally difficult to know just when to spray. Hot dry weather was desiccating the crop prematurely in many areas. Nevertheless, our trials continued in an effort to discover the effects of this weather on desiccation.

The wheat trials south of Winnipeg were ready to spray 72 days after seeding, were harvested 14 days later, with marginal time advantages over swathing. The wheat trial at Minnedosa was sprayed 83 days after seeding, harvested 15 days later, while the balance of the field came off at 18% moisture 35 days later.

Flax fields proved to be very uneven this year. Desiccation with glyphosate proved to be most valuable under these conditions. In almost every case maturity ranged from the initial bloom stage to fully mature and dry at the time of spraying. Desiccation with glyphosate is slow enough to allow for many of the immature seeds to mature. In all cases desiccated crops were harvested earlier and without sacrificing yield or quality. In one trial rain a week after spraying caused the balance of the field to tiller and flower again, resulting in another crop stage. The desiccated area was harvested 15 days after spraying while the balance of the field re-bloomed. The result was a difficult harvest a month later with no compensating yield increase.

Canola proved to be a difficult crop to desiccate this year. Hot dry weather, combined with the small leaf area involved when canola is ready to spray reduced the effectiveness of this application. Seed shatter was not a major problem, but this year seed pods dropped prematurely, causing some yield reductions. Trials in Saskatchewan did not experience the same degree of pod dropping, perhaps due to more normal weather conditions, and also no loss in yield.

Summary of 1988 Focus On Inputs Desiccation Trials Earlier Harvests Harvest Dates - Desiccated & Swathed Focus On Inputs Trials Manitoba 1988

This chart compares the effectiveness of desiccating compared to conventional swathing. It also demonstrates the length of crop dry down time using a desiccant vs. swathing. On average, desiccated flax was harvested 16 days before the adjoining swathed flas; desiccated wheat gained 20 days on swathed; and there was little difference with barley or canola. These results do not take into account that with one flax trial the desiccated area was harvested this fall, whereas the balance of the field is under the snow. The results on the barley and Canola do not reflect last year 5 results which showed a marked advantage in favor of desiccation.

Lower Moisture at HarvestGrain Moisture at Harvest Focus On Inputs Trials Manitoba 1988

Grain moisture levels were taken on both the desiccated trials at time of harvest as well as the standing or swathed crop at that time as well. This table shows the efficiency of glyphosate to desiccate.

On average the 1/2 litre rate of glyphosate equaled the higher rates in terms of dry down. The exception to this was on Canola where a higher rate gave lower harvest time moisture levels. Desiccation lowered flax by 10% points, wheat by 7% points, and had no significant change to barley and canola. It should be pointed out that in both these trials the desiccant was applied somewhat on the late side, and more importance was placed on assessing perennial weed control on these trials.

Grain Yield Results

Grain Yields With Desiccation

Focus On Inputs Trials

Manitoba 1988

This table shows the results of yield comparisons among different rates of glyphosate and a comparison to swathed areas adjacent to the trial. Overall there were no significant differences between treated and swathed plots. The exception to this is the canola trial at Minnedosa where yield losses were measured. This requires further explanation. This trial was only 146 metres long, and was centered on a thistle patch which included a majority of the trial. We did observe some pod loss prior to harvest; but catch pans placed in the field prior to harvest showed only a few seeds shattered due to harvesting. It is difficult to assess yields under variable conditions, but we feel that the differences shown reflect more the weed pressure in the trial rather that the influence of the desiccant.

It should be noted that Focus On Inputs sponsored research on Agriculture Canada stations and on independent research stations on 9 sites across the Prairies in 1988 to assess the affects of desiccation on yield and grain quality. This data will be released as soon as it becomes available.

PERENNIAL WEED CONTROL

Last year our trials demonstrated that glyphosate appeared to do a good job of killing thistles and to a lesser degree, quack grass when applied as a desiccant. To achieve results the higher rates of 1 and 2 litres per acre were required.

The first slide demonstrates the effect glyphosate has on thistles when sprayed at the late bud stage, which coincides with the right time for desiccation in most cases. After harvest this field turned green with thistle regrowth except in the area which was desiccated.

The slide of this same field this spring prior to seeding shows the control of thistles still very evident.

This slide of the same field sown to wheat is a dramatic example of the continuing effect killing the thistles in the fall.

This field was desiccated in the fall of 1987, seeded to wheat in 1988, and the desiccated area from 87 yielded 30 bu/acre while the balance of the field yielded 15 bu/acre.

In 1987 16 out of 24 desiccation trials had moderate to severe thistle problems. Regardless of cultural practices every one of those trial areas showed better control of thistles in 1988. Yield increases from this control ranged from 15% to 50% greater yields.

Control of quack grass is similar to a normal fall application of glyphosate. Results were superior when growing conditions were most favorable and crop canopies did not interfere with spray coverage. The 1 and 2 litre/acre rates gave reasonable control into the second year.

One trial in Brandon included a large patch of perennial smartweed. The 2 litre rate gave satisfactory dry down of the weed, but long term results will not be known till next year. Call Bill Campbell next summer.

It appears that a consecutive desiccation program would be effective in controlling perennial weeds such as Canada Thistle, Sow Thistle and Quackgrass. The Association has integrated this concept into its research plans in 1988. Results will be evaluated this coming year.

Affects of Glyphosate on Seed Germination

Germination Test Results

Focus on Inputs Trial

Argyle Barley 1988

The use of glyphosate appears to have a detrimental affect on the germination of the harvested seed. This graph depicts a typical response.

The untreated seed produced 97% normal germinating plants. Seed from the 1/2 litre plot produced 25% normal germinating plants and 72% abnormal. The young plants all showed good shoot development but reduced root development. This trend has been consistent with cereal and oilseeds, and is most pronounced on the earlier sprayed, less mature crop. Some crops such as peas do not show damage as consistently.

This is another area under current research through our cooperative research with Ag Canada stations.

ANNUAL WEED CONTROL

The control of annual weeds in the crop does not result in any yield increase because any yield loss occurs prior to desiccation. However, the excellent annual weed control does provide for a drier seed sample, and in some cases, an easier harvest. We also observed that glyphosate provides complete kill; whereas swathing often cuts of f the tops and induces weed growth especially following a rain. This is particularly troublesome if the weed growth penetrates the swath.

In most trials annual weed growth was considerably reduced by desiccation. Hot dry weather " hardened" some weeds and resulted in reduced weed control.

GLYPHOSATE RESIDUE TEST RESULTS

Seed samples from all plots sprayed and harvested in 1987 were analyzed by an independent laboratory: Harris Laboratories. Regardless of the trial, glyphosate residues were below the levels of detection in all samples. This year Focus On Inputs has provided Ag. Canada in Regina with the necessary equipment to analyze all samples drawn from the 1988 research trials. We expect that results will be known in the next month

OTHER OBSERVATIONS

Harvesting of desiccated crops appears to be easier, not only from the standpoint of straight combining, but also the straw appears to breakdown easier, and green weeds are not a problem. Flax is especially nice to harvest, and some farmers felt that the combine could harvest 15% to 25% more due to the ease of harvesting.

Barley was the only crop where straw strength appeared to be lacking. Heavy Argyle barley broke at about knee height and lodged. Yield losses were prevented by straight cutting low to the ground, but this requires extra fuel and expense. In all other trials, even when harvest was delayed, desiccated crops stood up well, and dried up quickly after a rain.

GROUND APPLICATION

Many people expressed concern over potential loss of crop due to tracking of ground application through the crop at the time of desiccation.

Two factors control the potential losses: wheel width and boom width. We used 10 inch tires on the 256 Versatile, and with a 43 foot boom less than 4% of the area is trampled. Increasing the boom width reduces this loss further.

In actual practice yield comparisons never showed a 4% loss. This may be due to the fact that the crop is still quite green at the time of application, and to a certain extent, bounces back. The 256 Versatile had adequate clearance to avoid under the belly damage.

Harvesting in the opposite direction to sprayer movement also resulted in picking up a lot of the bent over crop. In most trials damage was 2% or less.

Will the use of glyphosate fit into 0-till cropping? I believe that it will, and in the process give us easier harvests, control of perennial and annual weeds, and make the handling of crop residues easier as well.

I would like to express my thanks to the farmers who cooperated with us in this field research. I received total support from all co-operators, in all areas. Several people went the extra mile in helping us. I owe an extra special thank you to Bob McNabb, Bill Campbell, for providing field sites and special equipment, and to Wayne Burton for harvesting all of the trials in the Minnedosa area. Owen Beaver and Jim Bambridge supplied the weigh wagon and technical assistance, for which we are much appreciative.